Synonyms for Embryonic:

adj.

beginning (adjective)
incipient, primal, foremost, budding, formative, preparatory, nascent, infant, primeval, initial, genesis, Commencing, fetal, primordial, original, aboriginal, baby, preliminary, alpha, maiden, newborn, introductory, infantile, emerging, first, inaugural, hatching, sprouting, early, precursory, Dawned, beginning, starting, new, germinal.
earliest (adjective)
original.
incomplete (adjective)
insufficient, unfulfilled, short, sectional, unsatisfactory, fragmentary, fractional, deficient, unachieved, undone, lacking, partial, segmental, scanty, immature, discontinuous, patchy, unattained, Unaccomplished, unfinished, missing, Curtailed, incomplete.
original (adjective)
primeval.
rudimentary (adjective)
beginning, germinal, immature, undeveloped, early, incipient.

n.

amniocentesis, birth, baby blues, amniotic fluid, baby shower, the afterbirth, arrive, anti-choice, antenatal, bear. dynamic, progressive, in its infancy, fledgling, in the making. embryonic (noun)
early, embryonal, embryotic, in embryo, embryo, immature.
incipient (noun)
undeveloped, rudimentary.

Other synonyms:

fledgling, dynamic. progressive. immature
rudimentary.
Other relevant words:
antenatal, in embryo, rudimentary, embryo, undeveloped, in its infancy, embryotic, progressive, embryonal, fledgling.

Usage examples for embryonic

  1. But daily observation and history show us that in the realm of embryonic and ill- proven sciences this disposition is more flourishing than anywhere else. – Essay on the Creative Imagination by Th. Ribot
  2. That this Life also, even in the embryonic organism, ought already to betray itself to others, is certainly what one would expect. – Natural Law in the Spiritual World by Henry Drummond
  3. Real history is of course impossible to young children, whose idea of time is still very vague, and whose understanding of the motives and actions of those immediately around them is but embryonic – The Child Under Eight by E.R. Murray and Henrietta Brown Smith